Well, the SMPS it have a main advantage: is very energy efficient. Then it not dissipate heat, and is quite cheap to produce it.
The linear PSU it lose a important part of its energy effectiveness by dissipating it in heat. Exhausting the heat it may be a challenge in some particular cases. Also the transformer is an enough heavy/big, and quite costly part of such linear device...
However, when to compare it functional on a targeted device, the linear power it come far better, regarding the impact over the final result. Also some reasonable appreciations have to be made it, when deciding the use of a linear PSU instead of a SMPS one. The overall power the targeted device may need it. There is not so rational to use a linear PSU to power a whole computer, which it may need hundreds of watts... Here a SMPS is far more rational to use it. In my opinion, a SMPS is not a PSU which is just the right one to use it in a hifi audio device...
There is another aspect when to use a SMPS for a digital stage: its large spectre noises become mixed in a enough complex way with the HF noises issued by the digital activity itself. A SMPS it will always increase the overall noise level into a system. In opposition, a linear PSU (which it not generate HF noises at all), it contribute to lowering the overall noise level into the same digital system.
However, everybody can make some simple measurements (a scope may be needed) to see/experience himself the noise differences, as the positive impact of using a linear power for a targeted digital system.

Linear PSU it generate indeed an amount of HF, if one should go deep into details and analyse it as an electronic device. At least every electronic device it generate more or less HF noises. The point here is that the differences in HF generated noises, between an SMPS versus a linear PSU, it are enormous. While a good "silent" SMPS noise level is in teens mV range, the linear PSU it is in ÁV - nV range. While a SMPS noise spectre is very large for quite high levels, the linear PSU noise spectre is very limited with levels bearable measurable...
Very important is to remember in this discussion (quite OT for this thread), that there is not about powering a analogue stage with a SMPS or linear PSU, but a digital stage. A digital stage is noisy by its nature (much more noisy than the noises generated by a linear PSU). Using a SMPS to power a such digital stage it increase the overall noise level into the system. Powering the same stage from a linear PSU it lower the overall noise level in the processing system.

After this enough extended PSU discussion, I may suggest we go back to the real topic of this thread: Oppo Sonica DAC...

The great news is that the ES9028pro DAC chip is pin compatible with the ES9018, by design. Makers can use the new, much improved 9028pro with a minimum of effort. Updated firmware to allow selection of pre-programmed filters and other new features is a much smaller effort than a board re-design. Chinese makers like Gustard made the upgrade months ago, and hopefully Oppo can too in 2017.

You've seen the internal photo posted by Oppo. The shipping product has one notable difference: a strange ceramic block atop the ES9038pro dac chip. Also visible are the output traces from the dac to the I/V and output buffers. The balanced sections are on the outside and single-ended in the middle.

Much appreciated your contribution, with these detailed inside pictures here.

Old approach/design adapted to a new product. Minimal design improvements for the DAC section, as I can see into these pictures, compared with Oppo previous products..
Indeed, what a hack is that on the DAC chip top? It looks to me as a passive device.
Has Oppo adopted in the last time a mystical way of electronic design? A kind of "bybee" device on top of the DAC chip to improve its performances? I should expect a heatsink on the top of the DAC, as a more logical approach, but this ceramic (or whatever material may be) device is very strange indeed...
A DAC chip capable for -140dB dynamics, used into this Sonica, specified for -120dB dynamics, with a mystical ceramic device on its top for improved performances?
This it looks to me quite astonishing as design concept... If this mysterious device is glued well on that chip, it may be a big problem for further (my) modifications in this area...
At least this kind of DAC heat it is hide now the marking on that chip... It is used a 9028Pro instead of 9038Pro, and this it is hidden by using this trick with a such ceramic cover...
I assume Oppo should explain soon what about this "unexplained" and unexpected design "invention"...

I'll surely buy a Sonica DAC in the near future but so far I hadn't read any reviews of how amazing this dac sounds out the box, perhaps it isn't that good after all.

The other thing holding me up it's that white cap over the chip, it's like an attemp to keep a dirty secret under the hood. It looks like it's simply crimped to the pcb and it wouldn't be so hard to remove.

I recently contacted oppo, they don't seem very interested in selling this thing worldwide, only north america.

I think it may be very special if Sonica DAC it will sell it only in North America. I have informations that this DAC it may come soon to Europe too... A very limited number of devices it was already sold in Europe... Let`see...
Indeed it is a little bit strange that this product it was not yet reviewed.
Else it seems to be the only consumer DAC (for a reasonable price), which it have inside the newest ESS Sabre chip.t
It have to sounds very particular, as it have that ceramic hat over the DAC chip... Nobody did like this until Oppo came on this revolutionary idea... I can bet that we will see soon on Ebay such white briks for sale for the ones who may want to improve the sound of their (ESS Sabre based) DACs...
It could be ESS themselves which recommended a such device glued on the chip, for some mystical reasons or improvements?

Indeed. He got it already from US market, or is the one of the very few which it was exported to Europe...
My (ready) mods for this device it will come later, as I haven`t access yet to this product, and I can not buy it in Europe... Not happy at all about, but so it is...
I hope it will be later sold on European market too...